Synthesis, characterization and exploration of photovoltaic behavior of hydrazide based scaffolds: a concise experimental and DFT study

Abstract

Solar energy being a non-depleting energy resource, has attracted scientists' attention to develop efficient solar cells to meet energy demands. Herein, a series of hydrazinylthiazole-4-carbohydrazide organic photovoltaic compounds (BDTC1–BDTC7) with an A1–D1–A2–D2 framework was synthesized with 48–62% yields, and their spectroscopic characterization was accomplished using FT-IR, HRMS, ¹H and ¹³C-NMR techniques. Density functional theory (DFT) and time dependent DFT analyses were performed utilizing the M06/6-31G(d,p) functional to calculate the photovoltaic and optoelectronic properties of BDTC1–BDTC7 via numerous simulations of the frontier molecular orbitals (FMOs), transition density matrix (TDM), open circuit voltage (V_oc) and density of states (DOS). Moreover, the conducted analysis on the FMOs revealed efficient transference of charge from the highest occupied to the lowest unoccupied molecular orbitals (HOMO → LUMO), further supported by TDM and DOS analyses. Furthermore, the values of binding energy (E_b = 0.295 to 1.150 eV), as well as reorganization energy of the holes (−0.038–0.025 eV) and electrons (−0.023–0.00 eV), were found to be smaller for all the studied compounds, which suggests a higher exciton dissociation rate with greater hole mobility in BDTC1–BDTC7. V_oc analysis was accomplished with respect to HOMO_PBDB-T–LUMO_ACCEPTOR. Among all the synthesized molecules, BDTC7 was found to have a reduced band gap (3.583 eV), with a bathochromic shift and absorption maximum at 448.990 nm, and a promising V_oc (1.97 V), thus it is regarded as a potential candidate for high performance photovoltaic applications.